Plasma-Sprayed Nickel-Based Electrocatalysts with Molybdenum and Chromium Doping for Efficient Hydrogen and Oxygen Evolution Reactions

Producing hydrogen through water splitting holds significant promise for sustainable energy generation. This study demonstrates a scalable approach for fabricating highly durable nickel-composited NiX (X = Cr and Mo) electrocatalysts using atmospheric plasma spray, a versatile technique that enables rapid deposition with strong adhesion and ensures reliable performance under harsh electrochemical conditions. The electrocatalysts exhibited superior catalytic activity, with NiCr showing overpotentials of 327 mV for oxygen evolution reaction (OER) and 314 mV for hydrogen evolution reaction (HER), while NiMo required only 295 mV for OER and 243 mV for HER. In the two-electrode full-cell configuration, NiMo delivered a lower operating potential of 1.67 V at 20 mA cm–2, whereas NiCr needed 1.76 V. Both electrodes retained stable performance after prolonged cycling, and chronopotentiometric measurements at 50 and 100 mA cm–2 over 50 h further confirmed their excellent durability. In addition, the morphology and wettability changes before and after electrochemical reactions were systematically investigated to understand the catalyst surface behavior. Collectively, the findings indicate the potential of NiX as an effective material for overall water splitting and emphasize plasma spraying as a reliable strategy for fabricating high-performance electrocatalysts.